I bought a Nokia handsfree car kit for audio - the CarPC has a serial bluetooth connection for dialing etc, and the car kit gives much better sound quality and reliability than the CarPC can give through the audio gateway.

It's a CK-1W, which I believe has now been superceeded, but it works fine with my Nokia 6233.

I spent quite a long time in the early days trying to get the audio gateway to work on the car PC, which in prinicple is a more elegant way of doing it. However if you search about you'll see the connection isn't very reliable, sound quality is poor and not all phones work.

The car kit gives me great sound quality and reliable connection, and the car PC is able to dial out, displays incoming call details and can use the phone connection for internet - it's the best of both worlds, and the only downside is the additional cost and effort to buy and install it (and maybe 2 microphones if you want voice control of the PC).

So is your kit connected to you CarPC? Is your setup headless? How is audio routed? I have been looking for a handsfree solution since I started my CarPC efforts, and since Verizon (or CDMA in general) don't seem well supported on the CarPC I would look closely at such a solution.